Prevalence of abnormal liver enzyme tests during asymptomatic
screening is not uncommon, estimated to be 1-4% by some author (Scand J
Gastroenterol 1986;21:106 Hultcrantz R), and is up to one-third of patients
screened by others (Mayo Clin Proc 1996; 71:1089 Patrick S. Kamath).

In choledocholithiasis, an AST increase is the earlist abnormality detected,
& usually < 5X. The AST increase is typically transient &
returns to normal within 72 hours.

In cholangitis, the AST increase can be up to 10-fold.

In viral and drug-induced hepatitis, the AST, ALT levels steadily increase
and peak in the low thousands range within 7-14 days. In uncomplicated
viral hepatitis, the transaminases return to normal in about 6 weeks.

In ischemic hepatitis, the transaminase abruptly increase within 24 hours
and may even be higher than 10,000 IU/L.

In acetaminophen overdose or in herpes simplex hepatitis, the transaminase
increases greater than 10,000 IU/L are also noted.

It is also elevated in bone disease, pregnancy, hyperthyroidism, lymphoma,
hypernephroma, cardiac failure. Patients with blood group O and B who
are secretors can have increased alkaline phosphatase after eating a fatty
meal because of the release of the intestinal enzyme, therefore the test
must be performed in fasting patients.

Gamma-glutamyltransferase (GGT) test is recommended to confirm the hepatic
origin of the elevated alk.phosphatase. It is the most sensitive marker
of biliary tract disease.

Interpretation AbnormalBiblirubin elevation:

Normally, the total bilirubin level is less than 1.1 mg/DL, & approximately
70% is indirect (unconjugated) bilirubin.

Unconjugated hyperbilirubinemia (> 80% of the total bilirubin is indirect)
suggests hemolysis or Gilbert's syndrome. The bilirubin level is usually
< 6.0 mg/DL.;

Conjugated hyperbilirubinemia (> 50% of the total bilirubin is direct)
suggests hepatocellular dysfunction or cholestasis.
When the bilirubin level is > 25-30 mg/dL, extrahepatic cholestasis is
an unlikely diagnosis, because the predominantly conjugated bilirubin is
water soluble, it is excreted easily by the kidney in extrahepatic cholestasis.

Nonalcoholic Steatohepatitis (fatty
liver): perhaps the most common cause of mildly elevated liver enzymes
in the US. It is commonly seen in patients with obesity, diabetes,
hyperlipidemia, medications, & jejunoileal bypass surgery.